To provide a pneumatic bias tire for heavy load in particular using a mono-strand bead as a bead and capable of efficiently suppressing the both of deformation of the bead shape in vulcanization molding and breaking of a ply cord in using a tire.

This pneumatic bias tire is provided with paired beads 2 and a bias carcass 3 formed by stacking, at least, two plies 3a-3f, whose both ends are fixed to the beads 2 respectively and which are formed by covering an organic fiber cord with rubber, with mutual organic fiber cords crossing to each other. The bead 2 is the so-called, mono-strand dead with approximately polygonal cross section formed by spirally winding a wire 4 into a prescribed row and stage and is characterized in that, at least, a flipper 7 having the wire is disposed between the bead 2 and the bias carcass 2, covering at least a corner part 6 positioned inward in the tire diametrical direction of the bead 2.